Measured service telephone system



OC. 22, 1940. H. TPFER 2218,63()

MEASURED SERVICE TELEPHONE SYSTEMA Filed Jan. 50, 1957 2 Sheets-Sheet lFIG.

a u /b 2b Si SZ b 3s T. u I ga I 751 u HERBERT TOPFER ATTORNEY.

C. 22, 1940. H TPFER MEASURED SERVICE TELEPHONE SYSTEM 2 Sheets-Sheet 2Filed Jan. 30, 1937 FIG. 2

Y sra 1N VEN TOR. HERBERT TOPF E R ATTORNEY.

BY K

Patented Oct. 22, 1940 hliill'l'tl@ S'EES Param orties 2,218,630NMASURED SERVICE TELEPHONE SYSTEM Germany Application January 30,1937,.Serial No. 123,227

. in Germany February 14, 1936 6 Claims.

The present invention relates to a circuit arrangement for meteringvariously related calls in remote communication systems and moreespecially for telephone systems in which the meter- 5 ing isregistered, in which the reckoning of the fee by influencing the meterof the calling subscribers line only takes place after a denite time forexample at the end of the call.

The invention aims at simplifying the devices l0 for determining theamount of the fee in accordance with the time and zone of the callrelative to the known arrangements of this kind and this is achieved inthat a special group of contacts is provided for each traic zone in thecontact bank 15 or banks of the assessor containing a number ofswitching positions corresponding to the .greatest number ci meteringimpulses which have to be transmitted for a call in the desired callZone.

1n the known arrangements of this kind it is zo necessary to provide azone switch, a time switch and an assessor. The present inventionobviates the necessity of providing a separate time switch. On accountof the construction of the contact bank or banks of the assessoraccording to the 25 invention it is possible to use the devices servingto characterize and register the zone as a time switch. Furthermore theinvention hasI the advantage that it is particularly applicable insystems with a large number of traffic directions and B0 works even inthese systems with complete efciency.

In addition to the foregoing, the present invention is concerned with acircuit arrangement in which after the number of metering impulses 35 tobe transmitted has been characterized these impulses are transmitted bythe aid of an assessor. In known arrangements of this kind thecharacterizing of the number of metering impulses to be transmitted iselected in that a o particular contact in the contact bank of theassessor is characterized by the connection to it o1 potential. In thesearrangements when the time comes for effecting the metering the assessoris advanced in steps until it reaches the contact 5 which has beencharacterized. Thereupon a relay serving to terminate the metering isenergized over this contact.

These known arrangements have the disadvantage that when through thebreaking of a cable 5o or as a result of some other fault the potentialis not applied so-called prolonged metering takes place, i. e., theassessor is operated continuously since it finds' no meteringcut-offpotential and consequently transmits metering impulses con- .55tinuously. This objection is avoided by the (Cl. 17g- 7.1)

present invention in that a number of contacts in the contact bank ofthe assessor equal to the number of impulses which have to betransmitted to the calling subscribers meter for the call establishedare connected to potential by switching devices (zone switch, timeswitch) determining the amount of the fee to be charged.

One embodiment of the invention is represented in the drawings'.

Figs. 1 and 2 show the various circuits o a repeater when takentogether. Fig. 2 should be placed at the right of Fig. l.

The arrangement shown represents a repeater of which the following are'the important parts.

(1) A rotary switch DG This rotary switch possesses four wipers and isset by the rst impuls-e train transmitted from the calling station andoperating on the repeater for the purpose of determining the tratcdirection. The zone of the call is characterized over wiper gl. Therotary switch is used for determining the duration of the call after ithas functioned as a zone switch and the zone characterization has beentaken over by another switching device. This function of determining theduration of the call isexercized by wiper g2 which is speciallyconstructed. Wiper g2 consists of a contact segment bythe aid of whichitA is possible to connect together allthegcontacts over which thesegment g2 passes in the course of its motion. If a conversation lastsfor example for 8 minutes and the contact segment g2 is advanced onestep for each minuteA all the contacts l-8 are connected together `andare maintained connected by the contact segment. I

2) The m'rotof switch DM with its two motor windings I and II This motorswitch has ten wipers of which wipers ml to m8 likewise serve for zonecharacterizing. The mode of operation of the motor switch DM forcharacterizingthe zone is that the motor switch is advanced by the-second characterizingA digit transmitted by the calling' subscriber inlarge steps and is advanced by the third characterizing digit in smallersteps'. The wipers mi to m8 are disposed in series with the wipergl ofthe rotary switch DG. A particular zone point, ZoI to ZoViII ischaracterized over wiper gl and one of the wipers mi to m8. The zonethus characterized is taken over by another switching device askdescribed abovev so that the motor switch DM is releasedfor otherpurposes. It is brought under the influence of an impulse sender.

which transmits impulses at intervals, for example ten seconds land inturn inuences the rotary switch DG arranged for determining largeintervals of time, for example minutes.

(3) The motor switch DA with its two motor windings I and II 'Ihis motorswitch serves as a zone assessor for transmitting the meter impulses atthe end of a call. After the characterizing of a zone by the rotaryswitch DG and the motor switch DM the assessor DA hunts for the zonecontact which has been characterized and remains on this contact untilthe termination of the call. When the time comes for metering, i. e.,when the calling station has given the clearing signal the motor switchDA is started up from the vpoint on which it has been set and isadvanced to a contact characterized by wiper g2 of the rotary switch DGnow serving as a time switch, thereby transmitting one metering impulsefor each step.

(4) The control switch DS The control switch DS supervises the mode ofoperation of the switching devices which have been mentioned anddetermines the time at which the individual switching operations arecarried out. It possesses 16 contacts. The contacts which are closed inthe individual positions are designated by Sti- Stia The manner ofoperation of the control switch is known per se. Its application for thepresent purpose may be seen from the detailed description.

The mode of operation of the repeater which is here represented will nowbe described in detail.

It will be assumed that the repeater is disposed beyond the first groupselector. When the preceding group selector is set on the repeater shownthe latter is seized over the c-lead. The control switch stands in itsstarting position in which all the contacts designated by Sti areclosed. Thus the following circuit is completed for relay C in therepeater: earth in the preceding group selector, lead c, a contact whichwhich is closed in position Stl of the control switch, winding II ofrelay C, battery and earth. Relay C' closes contact 10c and therebycompletes the following circuit for the winding of relay S: earth,contact 10c, control switch contact Sti, winding of relay S, resistanceWil, battery and earth. Relay S locks up in the following circuit whichis independent of the setting of th-e control switch: earth, contact10c, Gils, winding of relay S, resistance WiiZ, battery and earth. Atthe same time the following circuit is completed for the stepping relayF of the control switch: earth, contact 16e, resistance Wil l, controlswitch contact Stl, winding I of relay F, resistance Wig, battery andearth. Relay F energizes in this circuit and closes the followingcircuit for magnet DS of the control switch: earth, battery, magnet DS,contact Blf, resistance Wil and earth. By the closing of contacts 63dewinding I of relay F is short-circuited so that this relay releases andat contact tlf breaks the circuit for magnet DS. They control switch isthus stepped from position I to position 2 so that all the contactsdesignated by StZ are closed.

Winding I of relay C is operated in the seizing circuit this relayhaving previously been shortcircuited by the control switch contact StlThe repeater is now ready to receive the impulse trains transmitted bythe calling station. Pelay S closed contact 3s and thereby connectedwinding I of the impulse receiving relay A to the upper speaking lead.The impulses transmitted by the calling station operate relay Aintermittently over the following path: earth in the preceding rst groupselector, impulse Contact in the group selector, upper speaking lead a,contacts Ib, 3s, Winding I of relay A, battery and earth. The speakingleads of the repeater passing to the following connecting devices areswitched through by relay S at contacts |63 and ils, so that theimpulses transmitted to the succeeding connecting devices from thecalling station are transmitted to the succeeding connecting devicesover the following path: earth, contact lh, contact lila operatedintermittently, the upper speaking lead, contact |63 and further to thesucceeding connecting devices. Relay A also intermittently operates itsContact Sia so that magnet DG of the rotary switch receives impulsesover the following path: earth, con-tact 5 la, winding III of the relayV, control switch contact St2, magnet DG, battery and earth. Wipers glto g4 of the rotary switch DG are accordingly brought to a particularposition corresponding to the impulse trains transmitted. In the abovecircuit for magnet DG is arranged also winding III of relay V whichrelay also energizes. This relay at contact illu short-circuits itswinding I so that it operates as a slow-to-release relay and bridgesover the gaps between the individual impulses of' the impulse train.Thus relay V only releases some time after the last impulse istransmitted. Through the opening of contact i311 the upper speaking leadis cut off during the transmission of the individual impulses in order ito avoid disturbance from the side of the calling subscriber. followingcircuit is established for the stepping relay F of the control switch:earth, contacts 52a, 13u, wiper g4 of the rotary switch DG in theoperated position, control switch contact St2, winding I of relay F,resistance W'iil, battery, earth. Relay F causes the control switch toadvance in the manner already described, so that it steps to position 3.When the calling station transmits the next impulse train, relay A isagain influenced over its winding I in the same circuit as in the caseof the first impulse train.

By the closing of contact 9a the following circuit is set up for relayV: earth, contacts lic, 9a, control switch contact StB, windings I andII of relay V, battery and earth. Relay V energizes in this circuit andagain holds its contacts operated throughout the impulse train. At thesame time, as in the case of the first impulse train, the followingcircuit is completed for relay Y: earth, contacts Hc, 9ct, winding I ofrelay Y, battery, earth. Relay Y energizes intermittently in thiscircuit. Special switching operations which are important in connectionwith the arrangement to be described are not initiated by relay Y atthis moment. It will merely be mentioned that relay Y serves to releasethe seized repeater in the event of the subscriber failing to transmitany impulse train for a prolonged period. In addition, it serves thefurther purpose of preventing the metering operation from being cutshort, which may happen by the calling subscriber preventing the normalsetting of the devices serving At the end of the impulse train the todetermine the number of metering impulses of contacts 55a and 51a, theimpulses of the second impulse train operating on the repeater aretransmitted to the motor switch DM. Over the control switch contact St3and contact 5th), earth potential is applied to the cam contact fi'imkofthe motor switch. Winding II of the' motoris accordingly operatedover: earth, contact 50o, control switch contact StB, cam contact Mmkoperated by the motor, winding .II of the motor, battery, earth. Themotor is, however, not able'to start up at once since winding I ofk themotor is also operated and thus no turning moment can be exerted on the'motor. The winding I of the motor is operated over the followingcircuit: earth, battery, winding I of the mctor, control switch` contactSt3, contact 56a., wiper m3 of Ithe motor switch DM in the startingposition, cam contact 41m7c, control switch contact St3, contact 5Go,earth. The motor switch can only advance its `wipers when, after the rstimpulse has terminated, contact 56a has opened and Contact 'aaccordingly closed. The wipers are advanced by only one step until wiperm9 rests on. contact 0. In this position, both windings of the motor areoperated over:

(l) Earth, battery, winding I of the motor, control switch contact St3,contact 57a, rest contact 0, ywiper m9 of the motor switch DM, camcontact Illmk, control switch contact St3, contact Stic, earth, and y(2) Earth, battery, winding II of the motor, cam contact 4'imc, controlswitch contact St3, contact 55o, earth.

.the windings of the motor are operated again at the same time, windingI over the circuit: earth, battery, winding I of the motor, controlswitch contact St3, contacts 56a, 55a., 'contact 1, wiper m9 of themotor switch, motor contact 4'imk, control switch contact St3,- contact56u and earth, and winding II of the motor in a manner which may beeasily seen from the drawings. When, after the end of the second impulseof the train, contact r57a. is again closed the switch DM can advanceits wipers to the 10th contact.` When this contact is reached by wiperm9, both windingsl of the motor are operated again simultaneously sothat the motor switch remains set and .can only be advanced when thenext impulse is received.

' In this way the wipers of the motor switch DM are advanced by 10 stepsfor each impulse received. Thus at the end of the impulse train, wiperm9 stands on a main resting position, thus for example, on contact I,20', 30, 40, etc.

Shortly after the termination vof the vlast impulse and after theVprotracted openingof'contact 9a, relay V releases. The control switch isadvanced from position 3 to position 4,.the

stepping relay F being energized over theffollow- When now the secondimearth. The control switch is advanced into position 4 in the mannerdescribed.

The next impulse train transmitted by-the calling station againinfluences windingI of re lay A in the manner described. The impulsesare repeated to the motor switch DM by the intermittent closing andopening of contacts 51a and 52a and the motor switch is now advancedonly one step for each opening and closing of the contact. the followingcircuit is set up: earth, contact 5ta, winding III of relay V, controlswitchcontact Std, cam contact 41m7c, winding II of the motor, battery,earth. In this circuit relay V energizes and again maintains itscontacts operated throughout the impulse train. Inaddition winding II ofthe motor is energized so that the associated contact mm2 is closed andnow both windings of the motor are operated over:

(l) Earth, battery, winding I of the motor,

cam contact 46mlc, control switch contact SM,- winding III of the relayV, contact 5in., earth,

Y impulse transmitted by the calling subscriber.

The first time that contacts Ela close Wipers vml to m9 of the motorswitch DM are f thus set on a definite contact. So long as relayVisstill energized, the following circuit is established for winding Iof relay T: earth, control switch contact St4, contact 2512, winding ofrelay T, resistance Wit?, battery,'earth. When at the end of the impulsetrain relay V releases, the circuit for relay T is broken again but afresh circuit is completed for this relay at contact 26o: earth,control-switch-contact St4, contact 261), wiper gl of the rotaryswtchDG, a 'particular'contact in the contact bank of this wiper,

' one of the wipers ml to m8 of the motor switch DM, a contact inthebank traversed by this wiper, one of the zone leads ZoI to ZoVII,windingof relay T, resistance Wi3, battery and earth. Thus relay Tremains energized so that the following circuit is set up for thestepping relay F' of the control switch. DS: earth, contact 52a,

73o, it, control switch contact. St4, winding of relay F, resistanceWiS, battery, earth. The control switch thus proceeds from position 4 toposition 5. In position 5 also relay T is Amaintained energized, namelyover earth which is connected at wiper gl of the rotary switch DG overycontrol switch contact St5. Since relay T remains energized contact.181k also remains operated so that in position 50i the control switchthe circuit just set out for the stepping relay F of the control switchDS is established. Thus the control switch proceeds from lposition 5 toposition 6.

Relay T is the so-calledfzone testing relay. It Atests as to whether thenumerical impulse trains transmitted by the calling station correspondin their combination to a zone characteristic. It has been assumed .thatthe impulse trains transmitted do correspond to a zone characteristic.If, however, .this is not the case, i. e., if the calling subscribertransmits characterizing digits whose combination does not correspond toany zone characteristic, the setting of the wiper gl of rotary switch DGand the connected wiper of (75 the motor switch DM is such that nocircuit can be set up over these wipers for relay T. Thus after relay Vhas released and contact 25o hasv opened and contact 2612 has closed nocircuit obtains for relay T over the control switch contact Stil.Accordingly relay T releases before the control switch has been advancedfrom position 5 to position 6. Since contact 'it is now open the controlswitch in position 5 receives no fresh advancing impulse but remains inthe position in which it has been set. Accordingly the winding of relayS shown in the top right-hand corner of the drawing is short-circuitedover control switch contact S755. The locking circuit over contact 69sis thus opened so that relay S falls back. The succeeding connectingdevices are released by the opening of contacts its, I'ls, and |85. Therelease of the repeater with its associated devices can also take placein any known manner.

It will now be assumed that the characterizing digits transmitted by thecalling station correspond in their combination to a zonecharacteristic. It has. already been mentioned that the control-switchST in this case is advanced from control switch position 5 to controlswitch position 6. It may further be mentioned that since thecontrolswitch remains in position 5 only a very short time and theshort-circuit for relay S over control switch contact St only obtainsfor a very short time, relay S cannot release.

The calling subscriber now transmits the other numerical impulse trainswhich are repeated by contact lila. to thesucceeding connecting devicesand thus establishes the connection to the desired station. The devicesin the repeater are not inuenced by these impulse trains.

It will be assumed that the connection to the desired station has beenestablished and that the called party has replied. In this case batteryis applied to the lower speaking lead in a succeeding connecting device.The following circuit is established: earth, battery in the succeedingconnecting device, lower speaking lead, contacts Hs, '2211, controlswitch Contact StG, winding I of relay B, contacts 23h, 241, earth. Inthis circuit relay B energizes and opens contact 23h and thereby removesthe short-circuit about winding II of relay F. Relay F energizes, opensa further point in its short-circuit at contact Zl]c and closes contacts57i thereby switching on the magnet DS of the control switch. Thecontrol switch is thus advanced from position to position 1. The controlswitch contact StB is thus opened so that the above-mentioned circuitfor relays B and F is again broken. These two relays release.

In position 'l of the control switch earth is connected to cam contacts62st: and B'Balc of the motor switch DA: earth, contact 59C, controlswitch contact St?, cam contact 63alc and 62u76, winding II of the motorand winding I of the motor, battery, earth. 'The motor switch' operatesautomatically (by selfinterruption) and moves its wipers dal to dal!over the contact banks. The stepping of the motor switch continues untilone of the wipers of this switch has found a Zone contact ZoI to ZOVII,which is connected to earth over one of the wipers ml to m8 and wipergl. Assuming that a connection has been established in zone IV duringthe day time, the following circuit'is set up: earth, battery, windingof relay P, control switch contact S157, contacts 38u, 3511, wiper dalof the motor switch DA, zone contact ZOIV, wiper mt, contact 3, wiper gl,control switch contact St'l, earth. In this circuit the highlysensitive and rapidly testing relay P energizes and by closing itscontact Bip simultaneously operates both windings of switch DA so thatthe switch temporarily comes to rest. The following circuits are set upfor the two windings of the motor: earth, contact 59o, control-switchcontact S151, then on the one hand over contacts BSac and Blp to windingI and on the other hand over cam Contact 63a7c and winding II and thenbattery, earth. By the closing of contact 85pthe following circuit iscompleted` for the advancing relay F of the control switch: earth,contact 85p, control switch contact St'l, winding I of relay F, Wi9,battery, earth. The control switch is advanced in the manner previouslydescribed. It proceeds thus to position 8. In position 8 of the controlswitch the following circuit is set up: earth, control switch contactS158, wiper g3 of the rotary switch DG in the working position, contactidg of magnet DG, winding I of relay A, battery, earth. In this circuitrelay A energizes, closes its contact 5m and thereby completes thefollowing circuit for magnet DG: earth, contact 5Ia, control switchcontact StB, magnet DG, bat tery, earth. The rotary switch DG is thusadvanced one step. Contact lldg of magnet DG is broken and hence theabove circuit for relay A is also broken. Relay A accordingly releasesand opens its contact Ela again and accordingly breaks the circuit formagnet DG. Contact idg is again closed and relay A energized, which byclosing contact Ela operates magnet DG again. The reciprocal playbetween magnet DG and relay A is continued until the rotary switch DGreaches its normal position in which a circuit can no longer beestablished for relay A. The control switch is advanced from position 8to position 9 due to the following circuit being established for theadvancing relay F of the control switch: earth, contacts 52a, 13o, wiperg4 of the rotary switch DG in the zero position, control switch contactSt, winding I of relay F, resistance Wifi, battery, earth.

The motor switch DM is now advanced into its rest position, earth beingapplied to the cam contacts llmk and 4'lmlc of the switch over thecontrol switch contact 9. The motor switch is accordingly advancedautomatically (by selfinterruption) until it has reached its normalposition. When this is the case the rotary offnormal contact 'lwm isclosed and the following circuit is established for the advancing relayF of the control switch: earth, contacts 52a, 13o, rotary off normalcontact 151.11m, control switch contact 9, winding I of relay F,resistance Wz'9, battery, earth. The control switch passes from position9 to positionV l where it remains throughout the duration of the call.

The two switches DG and DM, which are now in the rest position and whosefunction of characterizing the zone has been taken over by the assessorDA can now be dispensed with as regards this purpose." They are now,after the called subscriber has replied, used to determine the durationof the call.

The following supplementary description will be given: In position 8 ofthe control switch, B is energized in the following circuit: earth,contact I lc, control switch contact St8, winding II of relay B, windingII of relay Y, battery, earth. Relay B thus applies earth to the upperspeaking lead only when the control switch 'reaches position 8, theearth being applied over contact 2b and winding I of relay E. When thecontrol switch passes to position 9 the circuit for relay Bis maintainedand in addition relay Blenergizes: earth, contact llc, control switchcontact S129, winding of relay BI, winding II of relay B, winding II ofrelay Y, battery,'earth. Relayl Y also energizes. A locking circuit isset up for all three relays over contacts |2b l. Y

As has already been stated the control switch remains in position Iduring conversation. After rel-ay Bil has energized a ten second switchis connected to winding II of relay A.v Relay A accordingly receivesimpulses every ten seconds over the following path: rtens-secondsswitch, contacts 8819i, 81e, rotary oi normal contact Swa ofthe assessorDA (closed when the assessor is off normal), winding II of relay A,battery, earth. The:` ten seconds impulses are transmitted tothe motorswitch DM over control switch contact Still by the closing of contactta. The motor switch DM is thus displacedby one step every ten seconds.By suitably wiring the contact bank of the motor switch DM the switch DGis arranged to be influenced only in particular positions of the motorswitch DM. The motor switchD'lVI thus totals up the tens-secondsimpulses and influences the rotary switch DG at larger intervals oftime. The wiring of the contact bank of motor switch DM is so arrangedthat for the rst three minutes of the call a single advancement of therotary switch DG takesr place, after the lapse of the free period, i.e., that period which is appointed to enab-le the calling party to.ascertain that the correct call has been set up,

only a small charge being made if the clearing signal is given withinthe period. After the iirst three minutes the switch DG is -advancedone' switch is advanced in steps (external control)- 'Ihus the motorswitch is` stepped on keach opening and closing of contact Sla..v Wiperm9 of this switch is thus advanced by the first ten seconds impulse toposition 0, by the second to position I, Vand the third to position 2.Thus in approximately 20 to 30 seconds wiper m9 is brought to contact 2and sets up the following circuit: earth, contact Ela, control switchrcontact Still, cam contact 41111.76 of the motor switch and then' onthe one hand to winding II of the moto-r and battery to earth and on theother Ahand over wiper m9, contact 2, control switch contact SMG, magnetDG, battery and earth. Thus the rst advancement of the rotary switch DGoccurs when contact 5ta is closed after wiper m53 has been set oncontact 2.y Wiper y2 passes into its rst switching position and remainsin this position for three minutes as will be'further described below.

As may be seen from the drawings, contact 2, in the contact bank ofmotor switch DM which is traversed by wiper m9, on which contact tlewiper m9 is set at the moment, is connected to a strip. On reaching anyof the switch positions which are connected over this strip the switchDG is advanced as is its wiper G2. The switch DG is stepped forward4asrnay be seerrfrom the drawings whenwiper m9 reaches contact IS, i.je., after conversation has lasted for three minutes. The nextadvancement takes place when wipermg `passes to Contact 4', i. e.,.after the conversationhas lasted for four minutes. The switch DG is nowadvanced one step per minute. The stepping of the switchfDG continues inthis way until .the termination of the call.

When the calling subscriber replaces his receiver at the end of the callbattery is connected to the upper speaking lead in the preceding groupselector. The following circuit is set up for relay E: battery potentialin the preceding group selector, the upper speaking lead, contact 2b,winding I of relay E and earth. Relay E energizes in this circuit,closes its contact 83e, and thereby completes the following circuitlforthe stepping relayk of the control switch: earth, contact 83e, controlswitch contact Slt! 0, winding I of rrelay F, resistance Will, batteryand earth. The control switch is thus advanced to position Il. In.position Il of the control switch, testing takes place as to whether themetering impulse receiving relay in lthe rst group selector which isconnected to earth andthe lower speaking lead has been duly connected tothis lead. If this is closed the following circuit is set up: earth,metering relay in the preceding group selector, lower speaking lead,control switch Sitl'l, resistance Wil, winding I of relay Sil, batteryand earth. Relay SI energizes and closes its contact 80st and therebycompletes the following circuit for rthe stepping relay F of the controlswitch: earth, contact st,

vcontrol switch contact Sti I, winding I of relay F,

. ation being maintained in the manner whichmay be seen from thefollowing description. Through the opening of contact 81e, the tenseconds switch was disconnected from the winding 1I of relay A. Thiswinding is immediately reoperated over: earth, contact 89C, controlswitch contact SH2, contact 86st, winding II of relay A, battery andearth. Relay A closes contact 54a" and thereby applies earth foradvancing the motor switch of the assessor. Earth, contact 5ta, windingIII of relay V, control switch contact SH2, cam contact 62a'lc and 630thof the motor switch'DA, motor windings I or II, battery :and earth. Byclosing contacts 64a and 65a (contacts 60e and 65e are also closed) thetwo windings of the motor are connected up so that the motor switch canonly advance step by step on each application of earth potential tocontactlyia. In the above circuit relay V also energized and closedcontact 5622 y and thereby set up the following circuit for relay SI:earth, contacts 5to, 58e, winding II of relay Sil, battery and earth.Relay -V has adefinite delay feature so that relay Si remains energizedfor a definite time. The result of this is that relay S is caused torelease since the following short-circuit is established for the windingof thi relay: earth, battery, resistance Wfz'i2, contact 123| controlswitch contact Stl 2, vcontact lilo, and earth. Relay S thus releasesand breaksk the leads passing to the succeeding connecting devices.Theseare thus released independently of the transmission of the.meteringimpulses. motor switch DA of the assessor is lthus stepped bythe rst closing of contact 5ta, from the zone contact on which it isset. Simultaneously by the application of battery toi-the lower speakinglead metering potential is-applied tothe lower speaking lead to thepreceding group selector and to the metering relay disposed therein',this takes place over the following path: earth, battery, resistanceWz`6, control switchcontact SH2, contact 6a, lower speaking lead to thepreceding group selector. The meter of the calling station thus receivesits iirst impulse and is advanced one step. Relay SI which was operatedby contact 50o on the rst closing of contact Ela opens its contacts858|, and thereby breaks the above circuit for relay A. Relay A openscontact ia and thus breaksl the circuit of relay V. At contact 50u thecircuit for relay Sil is broken and this relay releases. Relay A isreoperated, the next metering impulse is transmitted, the motor switchDA is advanced and relay V is energized by the closing of contact 863|.Relay V connects up relay Si again and this once more breaks thecircuitfor relay A. In this way the motor switch DA is advanced and ametering impulse is transmitted at each step.

A somewhat more detailed description must now be given of theconstruction of the assessor and its contact banks. In the presentembodiment the motor switch DA acting as assessor possesses four Wipersdal to dat. The associated contact banks are differently constructed,the diiference being in the distribution and multipling of the contacts.As may' be seen from the drawings the contacts of the contact banktraversed by wiper dal are divided into five groups of contacts. The rstcontacts of the individual groups are represented on a larger scale andare designated ZoI to ZoIV. The rst group ZoI comprises a single contactwhich serves at the same time as the normal position for wiper dal. ThisContact position plays no part except in the case of calls in zone I, i.e., for local calls as will be described later. y

The contact group associated with the starting contact ZoII comprises llcontacts excluding the rst contact. Of these the rst two contacts areconnected together. These first two contacts are connected to contacts|-3 of wiper g2 while the remaining contacts 4-I2 of wiper g2 areindividually connected to the corresponding contacts 4-12 of the contactgroup ZoII of the assessor.

The contact group starting on contact ZolII possesses l5 contactsexcluding the starting contact and of these the first three areconnected together. In addition contacts 5 and 6, 9 and I, i3 and i4 areconnected together. The inclividual sub-groups of contacts arerepresented by 3', 4', 5', etc., because the contacts or sub-groups ofcontacts are connected to the corresponding minute contacts of wiper g2.The sub-group 3 comprising three contacts is thus connected to contacts1 3 of wiper g2 and the individual contacts 4', 6', 1', ID', and I2' areconnected with the corresponding individual contacts of wiper g2 andsimilarly the sub-groups 5', 8', and l i comprisingv two contacts each`are connected to the corresponding individual contacts of wiper g2. Thecontact group starting with contact ZoIV comprises, excluding thiscontact, 23 contacts. Of these the rst ve constitute a sub-group and areconnected together. They are followed by 9 sub-groups each comprisingtwo interconnected contacts. The rst sub-group 3' is connected to theindividual position |-3 of wiper g2 and the sub-groups 4-|2 eachcomprising two contacts connected together are connected to thecorresponding individual contacts of wiper g2.

The contact group starting at contact ZoV is subdivided in a differentmanner which may be seen from thedrawings and is connected to theindividual contacts of wiper g2.

As may be seen from vthe drawings five contact groups starting withcontacts ZoI to ZoV are arranged in the contact bank traversed by Wiperdai. 'Illese contactgroups serve for reckoning 4 the fee chargeable forcalls in the traine directions ZoI to ZoV while the day tariff is beingcharged.

The contact bank traversed by wiper da2 contains the contact groupstarting with contact ZoVI, these serving both for the day and nighttariff. The bank traversed by wiper cia3 comprises the contact groupcorresponding to tarii direction ZoVII and includes two diierent contactgroups for the day and for the night tariff.

The contact bank traversed by wiperv da4 comprises contact groups fromZoI to ZoV which are involved in calls in the tariff directions ZoI toZoV while the night tariff is obtaining.

Wiper g2 of the rotary switch DG serving as a time switch is speciallyconstructed in that it is connected to a segment which passes over thecontacts of the contact bank with the wiper. Accordingly the saidsegment connects together all the contacts oiv the contact bank overwhich wiper g2 together with the segment passes in the course of itsmovement and in dependence upon the duration or the call. To wiper g2earth is connected over winding II of relay E and contact 29e.

Thus if for example the wiper togethei1 with the said segment rests oncontact l that is if a conversation has been in progress for 7 minutesthen in ythe case of calls in zone ZoII the rst six contacts areconnected to earth potential, in case of calls in zone ZoIII 8 and inthe case of calls in zone ZoIV 13.

It should also be noted that the first contact position of wiper g2 isgiven the reference l-3 because wiper g2 is only stepped forward fromthis position when conversation has been in progress for longer than 3minutes. For this reason also in the individual groups of contacts therst contacts are connected together to an extent corresponding to thezone so as to be able to take.

placed one step as described. The wiper of the assessor, for examplewiper dal, which is set on a zone contact is thus set on a sub-group 3so that the following locking circuit is established: earth, battery,resistance WZ'IS, contact 652g, 38u, 3611., wiper dal of the motorswitch DA, contact position 3', contact position |-3, wiper segment g2,contact 2te, winding II of relay E and earth. The lapse of time requiredfor this circuit to be set up is bridged by` relay E itself which ismade slow-to-operate to a certain extent on account of the short-circuitover its winding I through control switch contact SH2. Thisslow-to-release feature also serves to bridge over the intervals takenby the assessor to pass from one contact to another.

The mode of operation will be explained somewhat rnore clearly by someexamples. It will be assumed that a call has been set'up in the .traczone ZoIDS and has been in progress for 8 minutes. When the calledsubscriber replies wiperdal -is thus set on zone contact ZoIlI.` On thetermination of the call wiper g2v passes to the 8th contact so that allthe contacts l are connected together. When the time arrives for ef.-fecting the metering wiper dal is stepped forvward and the circuit forwinding II of relay E is maintained for 5 minutes then contacts l--S areconnected together by wiper g2. Starting from position ZoVI wiper da? isnow advanced in steps and transmits altogether 20 metering impulses,namely l2 impulses for the st 3 minutes and 4 impulses for each of the4th and 5th minutes. When wiper cm2 reaches contact position t relay Ecan no longer hold up and ymetering is thus brought to an end.

When at the end of the metering relay E falls back the following circuitis established for the stepping relay F of the control switch: earth,Contact 813e, control switch Contact SH2, winding I of relay F,resistance Wig, battery and earth. 'Ihe control switch now proceeds .toposition i3. In position i3 winding II of relay B is shortcircuited.Relay B falls back and opens contact 2b thereby removing earth from theupper speaking lead. This forms the criterion for the release of thepreceding group selector. Relay C in the repeater then releases. rIhefollowing circuit is set up: ear-th, contact c, control switch contactSH3, wiper g2 of the rotary switch DG in the o-'normal position, contact4tlg of the magnet DG, winding I of relay A, battery and earth. Relay Acloses its contact Ela and thereby completes the following circuit:earth, contact 5M, winding III of relay V, `control switch contact SH3,magnet DG, battery and earth. Magnet i: DG opens its contact idg andthereby breaks the above circuit for relay A. The circuit for mag,- netDG is accordingly broken at contact Ela.

RelaylA is operated again by the closing of contact lldg, and theclosing of contact 51a reoperates magnet DG. The reciprocal play betweenmagnet DG and relay A proceeds until the rotary switch DG has reachedits normal position in which relay A can no longer be operated. Thefollowing circuit is now set up kfor the stepping relayl of the controlswitch: earth, contact 52a, 13o, wiper ge, in rest position, controlswitch contact SH3, winding I of relay F, resistance Wifi, battery andearth. The control switch thus steps from position I3 to position i4. Inposition I4 earth is applied to the cam contacts Smic and li'lmlc of themotor switch DM; earth, control switch contact Stld, cam contact Mmk ofthe motor switch DlVl, motor winding II, battery and earth. The motorswitch is thus automatically advanced (by self-interruption). When itreaches the normal position its rotary off normal contact mm is closedand the following circuit is established: earth, contacts 52a, ISU,rotary oil normal contact 'l5wm, control switch contact Stld, winding Iof relay F, resistance Wig, battery and earth. Relay F causes thecontrol switch to step to position l5. From position l5 the controlswitch is immediately stepped to position iii and further to itsstarting position I: earth, control switch contacts `SM5 and Stl,

winding `I `of relay F, resistance Wi9, battery and earth.

Y The repeater together with all its associated.

devices is oncemore in the normal position.

In rthe case of calls which are charged according to the low nighttariff naturally different fees from those in the case .of calls whichare established according to the day tariff must be reckoned with. Whenvcontact Sims is closed either by hand or by a .clock .contact when themoment for switching over to the night tariff arrives the followingcircuit becomes established when the control switch reaches position 6earth, contact at the night switch SONS, control switch contact Sit,rwinding of relay N, battery and earth. By .closing contact 3m relay Nlocks up, in a circuit independent of the control'switch. The contactsof relay N are accordingly operated during the whole time that the nighttariff is chargeable. As maybe seen from the drawings, wiperdal of theassessor is disconnected by the opening of contact 361i and Wiper dad,which ,computes the fee according to the night tariff,is

connected up by the closing of contact 311i. As may at once be seen fromthe drawings the contact groups for the night tariff in the individualtariff .Zones are so arranged in proportion to the corresponding contactgroups for the day tariff that they comprise fewer contact positions'.While' the night tariff is chargeable calls which are set up inv zonesII-V are metered by means of wiper dad. In the case of calls of zone VIthe contact group connected over contact tn is disconnected and in placeof it another Contact group is connected up by the closing of contact351i. This is also the case for calls in zone VII in which the contactgroup for reckoning the fee according to the day tariff is disconnectedby opening contact 4511 and is replaced by the .corresponding contactsfor the night tariff by f ance Wit, windingo'f relay T, winding I ofrelay U, wiper mil, wiper gl of contact 4, control switch contactSt3,contact 21o, and earth. Relay U which serves to connect up particularwipers of the motor switch DA in the same manner as relay R is energizedin this .circuit and locks lup over: earth, contacts 32e and 33u,winding III of relay U, battery andearth. By the opening of contact 38uwiper dal which as may be seen from the drawings is only concerned withcalls in zones ZoI-ZoV is disconnected and bythe closing of contact 39uwiper d`a2 which is used for computing the fee for calls in zone VI isconnected up.

If the call is set up in zone ZoVII a similar circuit to that describedabove is set up in which relaysU and R are energized, relay U beingoperated over its winding II and relay R over its winding I. Relay Ulocks up in the circuit already described while relay-R completes thefollowing locking circuit: earth, winding II of relay R, contacts 257'and 26u, resistance Wz'IS, battery and earth. Relay R opens contact 401,thereby disconnects wiper da2 which is only co-ncerned in .calls in zoneZoVI, and by closing contact lllr switches on wiper da3 which isprovided for computing fees in the case of calls in zone VII.

In the case of local calls it has to be arranged that no time meteringtakes place and that for each local call only a single metering impulse(5 is transmitted to the .calling subscribers meter. Wiper dal in itsrest position stands on zone contact ZoI, i. e., on the contact to whichearth potential is applied over one of the wipers m-m and Wiper gl inthe case of local calls. The assessor DA is thus not advanced in thecase of local calls but remains at rest. For this reason also the rotaryo-normal contact 96wa of this switch remains open so that the l0 secondsimpulse sender remains disconnected from winding II of relay A duringthese calls. Thus no time metering takes place but merely thetransmission of a single impulse on the termination of the call in theknown way.

What is claimed is:

l. In a telephone system having different Zones of calling and in whicheach calling subscriber has a meter operated to assess toll for callsdepending upon the zone called, a toll assessing switch, a special groupof contacts in the bank of said switch for each zone, each group havingas many contacts as required to send the greatest number of meteringimpulses required to assess toll for that zone, means for selecting agroup of said contacts in accordance with the Zone called and means formarking the selected groups in accordance with the length of said call,and means for starting the operation of said switch at the terminationof the call to send a number of impulses to the calling subscribersmeter, dependent on the contacts marked.

2. In a telephone system having calling lines and means for extendingconnections therefrom to called lines in different zones, a meter foreach calling line, a zone assessing switch having a wiper and specialgroups cf .contacts one for each zone, means operated during theextension of a connection for marking one of said groups depending onthe Zone called, and for then operating the wiper to find the group ofcontacts, means for thereafter marking the contacts of said marked groupbefore the connection is released, and means for starting the movementof the wiper over the marked group of contacts after the connection isterminated to operate the meter of the calling subscriber in accordancewith said last marking.

3. A telephone system as claimed in claim 2,

in which 'there is also a circuit controller, and means for operatingthe controller during the call to determine th-e number of times themeter will be operated by the zone assessing switch in moving over themarked group of contacts.

4. In a telephone system having calling lines and means for extendingconnections therefrom to called lines in different Zones, a step by stepswitch having wipers and a separate set of contacts for each zone, saidswitch operated during the progress of a call to bring the wipers intoassociation with only one of said sets of contacts, a device operatedduring the call for placing potential on the contacts of said associatedset in accordance with the duration of the call, and means for startingthe operation of the switch thereafter to operate the meter of thecalling line in accordance with the set of contacts selected and thenumber of contacts to which potential is connected.

5. In a telephone system having calling lines having meters and meansfor extending connections to called lines in different zones, theprovision of an auxiliary zone switch having a set of contacts for eachzone, means for determining that a particular set of contacts will beused to operate the meter of the calling line in accordance with thezone thereof, and a switch operated during an established connection forconnecting different numbers of the contacts in the different sets to apotential for each interval of time.

6. In a telephone system having calling lines and means for extendingconnections therefrom to called lines in different zones, a step-by-stepmeter assessing switch having wipers and a separate set of contacts foreach zone, a step-by-step switch operated during the extension of aconnection to mark a. particular set of said contacts in accordance withthe zone called, said last switch reoperated during the establishment ofa connection to mark a variable number of contacts in the selected set,and means for thereafter operating the assessor switch over the markedcontacts to transmit metering impulses in accordance with the markedcontacts.

HERBERT TPFER.

